Display device

ABSTRACT

A display device includes a substrate having display portion and peripheral portion, a plurality of gate signal lines and a plurality of drain signal lines formed over the substrate, a plurality of switching elements connected to the plurality of gate signal lines and the plurality of drain signal lines and formed over the substrate, and a plurality of pixel electrodes connected to the plurality of switching elements and formed in the display portion. An organic interlayer film is formed in the display portion and the peripheral portion, and a covering layer is formed on the organic interlayer film in the peripheral portion and the insulating film includes at least one of a plurality of recesses and protuberances.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 10/390,910, filed Mar. 19, 2003, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a display device, such as anin-plane switching(IPS) type liquid crystal display device or the like device.

2. Description of the Related Art

A liquid crystal display device of the so-called in-plane switching typehas been so constituted that the substrates are arranged opposed to eachother with the liquid crystals sandwiched therebetween, and pixelelectrodes and counter electrodes that produce an electric fieldrelative to the pixel electrodes are formed on the pixel region of onesubstrate on the side of the liquid crystals, and the liquid crystalsare driven by components of the electric field which are nearly inparallel with the substrate.

In the device of the active matrix type to which the above constitutionis adapted, the pixel regions are formed by those regions which aresurrounded by a plurality of gate signal lines arranged in parallel onthe surface of one substrate on the side of the liquid crystals and by aplurality of drain signal lines arranged so as to intersect the gatesignal lines.

Each pixel region is provided with a thin-film transistor that isoperated by a scanning signal from a gate signal line, the pixelelectrode supplied with a video signal from a drain signal line throughthe thin-film transistor, and the counter electrode supplied with asignal that serves as a reference to the video signal.

Here, the pixel electrode and the counter electrode are formed asstriped patterns extending in their respective directions. Theseelectrodes are usually formed in a number of two or more and arealternately arranged.

There has also been known a constitution in which counter electrodes areformed on the upper surface of an insulating film formed covering thedrain signal lines, the counter electrodes being formed along the drainsignal lines and having center axes thereof which are nearly inagreement with the drain signal lines and further having a width greaterthan the width of the drain signal lines.

This enables the lines of electric force from the drain signal lines tobe terminated at the counter electrodes instead of terminating at thepixel electrodes. The lines of electric force that terminate at thepixel electrodes turn out to be noises.

In order to decrease parasitic capacitance between the drain signallines and the counter electrodes in this constitution, the structure hasbeen known to interpose, at least, an organic material layer such as ofa resin as an interlayer insulating film between them.

It has, however, been pointed out that the liquid crystal display devicewhich is thus constituted permits the organic material layer to beeasily peeled off from the edges thereof in the step of production, theorganic material layer being peeled off up to the liquid crystal displayunit to cause defective display.

An inquiring of the cause revealed the following facts. That is, whenthe electrodes are formed on the upper surface of the organic materiallayer, the end surfaces of the organic material layer are exposed to aresist-developing solution, a peeling solution and to anelectrode-etching solution. These liquids for the resist-developing, thepeeling and the electrode-etching are for removing the residue of theorganic material layer. Among them, the developing solution is used fordissolving the uncured organic material layer itself, and the peelingsolution is used for removing the photoresist itself of the organicmaterial layer after it has played its role. These liquids have atendency of peeling the organic films off and, hence, the countermeasuremust be taken based upon this as a prerequisite.

SUMMARY OF THE INVENTION

This invention takes into account the above-mentioned circumstances, andhas as an object to provide a display device avoiding the peeling oforganic material layers.

Briefly described below are representative examples of the inventiondisclosed in this application.

According to a first embodiment of a display device of the presentinvention, there is provided, for example, a substrate having a displayportion and a peripheral portion, a plurality of gate signal lines and aplurality of drain signal lines formed over the substrate, a pluralityof switching elements connected to the plurality of gate signal linesand the plurality of drain signal lines and formed over the substrate, aplurality of pixel electrodes connected to the plurality of switchingelement and formed in the display portion, and a plurality of counterelectrodes formed adjacent to the plurality of pixel electrodes in thedisplay portion. An insulating film of an organic material layer isformed in the display portion and the peripheral portion, the pluralityof pixel electrodes and the plurality of counter electrodes are stripepatterns and have a portion bent in one direction, and a plurality ofdummy pixel electrodes and a plurality of dummy counter electrodes areformed in the peripheral portion.

According to a modification of the first embodiment of the presentinvention, for example, a number of at least either the plurality ofdummy pixel electrodes or the plurality of dummy counter electrodes ineach pixel region is greater than a number of the correspondingelectrode in each pixel of the display portion.

According to a second embodiment of the present invention, there isprovided for example, a substrate having a display portion and aperipheral portion, a plurality of gate signal lines and a plurality ofdrain signal lines formed over the substrate, a plurality of switchingelements connected to the plurality of gate signal lines and theplurality of drain signal lines and formed over the substrate, and aplurality of pixel electrodes connected to the plurality of switchingelements and formed in the display portion. An organic interlayer filmis formed in the display portion and the peripheral portion, and aninsulating film is formed between the substrate and the organicinterlayer film in the display portion and the peripheral portion, andthe insulating film comprises a plurality of recesses or a plurality ofprotuberances.

According to a modification of the second embodiment of the presentinvention, for example, the plurality of recesses or the plurality ofprotuberances are a plurality of openings formed in the insulating film.

According to another modification of the second embodiment of thepresent invention, for example, the plurality of openings are aplurality of holes in a scattered manner or a plurality of grooves inparallel.

According to a further modification of the second embodiment of thepresent invention, for example, the display device is a liquid crystaldisplay device, and the insulating film is an inorganic insulating film.

According to a further modification of the second embodiment of thepresent invention, for example, the display device is an organic ELdisplay device, and the organic interlayer film is a bank film of theorganic EL display device.

According to another modification of the second embodiment of thepresent invention, there is provided for example, a material layerformed between the substrate and the insulating layer to form theplurality of recesses or the plurality of protuberances of theinsulating film.

According to a further modification of the second embodiment of thepresent invention, for example, the material layer is made of a metallayer which is the same as the plurality of drain signal lines.

According to a third embodiment of the present invention, there isprovided, for example, a substrate having a display portion and aperipheral portion, a plurality of gate signal lines and a plurality ofdrain signal lines formed over the substrate, a plurality of switchingelements connected to the plurality of gate signal lines and theplurality of drain signal lines and formed over the substrate, and aplurality of pixel electrodes connected to the plurality of switchingelements and formed in the display portion. An organic interlayer filmis formed in the display portion and the peripheral portion, and acovering layer is formed on the organic interlayer film in theperipheral portion.

According to a modification of the third embodiment of the presentinvention, for example, the covering layer is formed on a portion of anend surface of the organic interlayer film in the peripheral portion.

According to another modification of the third embodiment of the presentinvention, for example, the covering layer is made of a transparentconductive material.

According to a further modification of the third embodiment of thepresent invention, for example, the covering layer is made of a materialsame as the plurality of pixel electrodes.

According to another modification of the third embodiment of the presentinvention, for example, the covering layer is made of a metal layer.

According to a further modification of the third embodiment of thepresent invention, for example, the covering layer is a testing terminalof the display device.

According to another modification of the third embodiment of the presentinvention, for example, the display device is an organic EL displaydevice, and the organic interlayer film is a bank film of the organic ELdisplay device.

According to another modification of the third embodiment of the presentinvention, for example, the covering layer is made of a material same asthe plurality of pixel electrodes.

According to another modification of the third embodiment of the presentinvention, there is provided for example, a plurality of counterelectrodes formed adjacent to the plurality of pixel electrode, and thecovering layer is made of a material same as the plurality of counterelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of pixels in a display device according to a firstembodiment of the invention.

FIG. 2A is a view of an entire equivalent circuit of the display deviceaccording to the first embodiment of the invention, and FIG. 2B is anenlarged circuit portion thereof.

FIG. 3 is a plan view of the entire display device according to thefirst embodiment of the invention.

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 1.

FIG. 6 is a sectional view of the display device according to a secondembodiment of the invention.

FIG. 7 is a sectional view of the display device according to a thirdembodiment of the invention.

FIG. 8A is a plan view of the arrangement of pixels in the displaydevice according to a fourth embodiment of the invention, and FIG. 8B isa sectional view taken along line 8 b-8 b in FIG. 8A.

FIG. 9 is a sectional view of the display device according to a fifthembodiment of the invention.

FIG. 10A is a plan view of the arrangement of pixels in the displaydevice according to a sixth embodiment of the invention, and FIG. 10B isa sectional view taken along line 10 b-10 b in FIG. 10A.

FIG. 11A is a plan view of the arrangement of pixels in the displaydevice according to a seventh embodiment of the invention, and FIG. 11Bis a sectional view taken along line 11 b-11 b in FIG. 11A.

FIG. 12 is a plan view of the pixels in a corner portion of the displaydevice according to a eighth embodiment of the invention.

FIG. 13A is a view of the arrangement of the display device according toa ninth embodiment of the invention, and FIG. 13B is a sectional viewtaken along line 13 b-13 b in FIG. 13A.

FIG. 14 is a sectional view of the display device according to a tenthembodiment of the invention.

FIG. 15 is a sectional view of the display device according to aneleventh embodiment of the invention.

FIG. 16A to FIG. 16F are views of material layers of the display deviceaccording to the eleventh embodiment of the invention.

FIG. 17A is a view of the arrangement of the display device according toa twelfth embodiment of the invention, and FIG. 17B is a sectional viewtaken along line 17 b-17 b in FIG. 17A.

FIG. 18 is a sectional of the display device according to a thirteenthembodiment of the invention.

FIG. 19A is a view of the arrangement of the display device according toa fourteenth embodiment of the invention, and FIG. 19B is a sectionalview taken along line 19 b-19 b in FIG. 19A.

FIG. 20 is a plan view of the display device according to a fifteenthembodiment of the invention.

FIG. 21A to FIG. 21E are views of edge shapes of the display deviceaccording to a sixteenth embodiment of the invention.

FIG. 22 is a sectional view of the display device according to aseventeenth embodiment of the invention.

FIG. 23 is a sectional view of the display device according to aneighteenth embodiment of the invention.

FIG. 24 is a sectional view of the display device according to anineteenth embodiment of the invention.

FIG. 25 is a sectional view of the display device according to atwentieth embodiment of the invention.

FIG. 26A is a view of the constitution of the display device accordingto a twenty-first embodiment of the invention, and FIG. 26B is asectional view taken along line 26 b-26 b in FIG. 26A.

FIG. 27 is a plan view of the display device according to atwenty-second embodiment of the invention.

FIG. 28 is a sectional view of the display device according to atwenty-third embodiment of the invention.

FIG. 29A to FIG. 29E are plan views of a method of producing the displaydevice according to the twenty-third embodiment of the invention.

FIG. 30 is a sectional view of the display device according to atwenty-fourth embodiment of the invention.

FIG. 31 is another sectional view of the display device according to thetwenty-fourth embodiment of the invention.

FIG. 32 is a sectional view of the display device according to atwenty-fifth embodiment of the invention.

FIG. 33 is another sectional view of the display device according to thetwenty-fifth embodiment of the invention.

FIG. 34A is a plan view of the constitution of the display deviceaccording to a twenty-sixth embodiment of the invention, and FIG. 34B isa sectional view taken along line 34 b-34 b in FIG. 34A.

FIG. 35 is a plan view of the display device according to atwenty-seventh embodiment of the invention.

FIG. 36 is another plan view of the display device according to thetwenty-seventh embodiment of the invention.

FIG. 37 is a further plan view of the display device according to thetwenty-seventh embodiment of the invention.

FIG. 38 is a further plan view of the display device according to thetwenty-seventh embodiment of the invention.

FIG. 39A is a plan view of the constitution of the display deviceaccording to a twenty-eighth embodiment of the invention, and FIG. 39Bis a sectional view taken along line 39 b-39 b in FIG. 39A.

FIG. 40 is another plan view of the display device according to thetwenty-eighth embodiment of the invention.

FIG. 41A is a plan view of the constitution of the display deviceaccording to a twenty-ninth embodiment of the invention, and FIG. 41B isa sectional view taken along line 41 b-41 b in FIG. 41A.

FIG. 42 is another sectional view of the display device according to thetwenty-ninth embodiment of the invention.

FIG. 43A is a plan view of the display device according to a thirtiethembodiment of the invention, FIG. 43B is a sectional view taken alongline 43 b-43 b in FIG. 43A, FIG. 43C is a sectional view taken alongline 43 c-43 c in FIG. 43A, and FIG. 43D is a sectional view taken alongline 43 d-43 d in FIG. 43A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the display device according to the invention will now bedescribed with reference to the drawings.

<Entire Constitution>

FIG. 2A is a plan view illustrating the entire liquid crystal displaydevice which is an embodiment of the display device of the invention.FIG. 2B shows an equivalent circuit of one pixel in the display device.

In FIG. 2A, a pair of transparent substrates SUB1 and SUB2 are arrangedopposed to each other through liquid crystals which are sealed by asealing member SL which also works to secure the transparent substrateSUB2 to the one transparent substrate SUB1.

On the surface of the transparent substrate SUB1 on the side of theliquid crystals sealed by the sealing member SL, there are formed gatesignal lines GL extending in the x-direction and arranged in parallel inthe y-direction, and drain signal lines DL extending in the y-directionand arranged in parallel in the x-direction.

The regions surrounded by the gate signal lines GL and by the drainsignal lines DL constitute pixel regions. A set of these pixel regionsin the form of a matrix constitute a liquid crystal display portion AR.In the pixel regions arranged in parallel in the x-direction, there areformed common counter voltage signal lines CL running through the pixelregions. The counter voltage signal lines CL are for supplying a voltageto the counter electrodes CT that will be described later in the pixelregions, the voltage serving as a reference to the video signals.

In each pixel region, there are formed a thin-film transistor TFT thatis operated by a scanning signal from the gate signal line GL of oneside and a pixel electrode PX which is supplied with a video signal fromthe drain signal line DL of one side through the thin-film transistorTFT. The pixel electrode PX generates an electric field relative to thecounter electrode CT formed in common (connected to the counter voltagesignal line) on the pixel regions on the surface of the transparentsubstrate SUB2 on the side of the liquid crystals. Relying upon thiselectric field, the light transmission factor of the liquid crystals iscontrolled.

The ends on one side of the gate signal lines GL extend beyond thesealing member SL, and constitute terminals to which are connected theoutput terminals of a vertical scanning drive circuit V. The inputterminals of the vertical scanning drive circuit V receive signals froma printed board arranged on the outer side of the liquid crystal displaypanel. The vertical scanning drive circuit V is constituted by aplurality of semiconductor devices, the plurality of gate signal linesneighboring to each other being grouped, and the semiconductor devicebeing assigned to each of the groups. Similarly, the ends on one side ofthe drain signal lines DL extend beyond the sealing member SL, andconstitute terminals to which are connected the output terminals of avideo signal drive circuit He. The input terminals of the video signaldrive circuit He receive signals from a printed board arranged on theouter side of the liquid crystal display panel. The video signal drivecircuit He, too, is constituted by a plurality of semiconductor devices,the plurality of drain signal lines neighboring to each other beinggrouped, and the semiconductor device being assigned to each of thegroups.

The counter voltage signal lines CL are connected in common at an end onthe right side in the drawing with the connection line extending beyondthe sealing member SL and forming a terminal CLT at an extended end. Avoltage that serves as a reference for the video signals is suppliedfrom the terminal CLT.

Any one of the gate signal lines GL is successively selected by ascanning signal from the vertical scanning circuit V. The drain signallines DL are supplied with video signals from the video signal drivecircuit He at timings for selecting the gate signal lines GL.

In the above embodiment, the vertical scanning drive circuit V and thevideo signal drive circuit He are semiconductor devices mounted on thetransparent substrate SUB1. They, however, may be semiconductor devicesof the so-called tape carrier system connected spanning across, forexample, the transparent substrate SUB1 and the printed board, or may bethe ones formed of the semiconductor elements of polycrystalline silicontogether with the wiring layer on the surface of the transparentsubstrate SUB1 when the semiconductor layer of the thin-film transistorTFT is constituted by polycrystalline silicon (p-Si).

As shown in FIG. 3, which corresponds to FIG. 2, the thus formed liquidcrystal display device has a display portion AR and a peripheralportion. In the peripheral portion, a dummy display portion DAR isformed as so-called dummy pixels in the pixel regions along theperiphery of the display portion AR. In this specification and in thedrawings, the liquid crystal display portion is denoted by AR and thedummy liquid crystal display portion is denoted by DAR.

The dummy pixels are constituted in the same manner as other pixels butdo not contribute to producing the display. The dummy pixels same tomake the value of the capacitor element Cstg in other pixels neighboringthe dummy pixels equal to the value of the capacitor element Cstg instill other pixels neighboring to the other pixels. Therefore, it issufficient if the dummy pixels are formed only in those portions thatare arranged in parallel with the gate signal lines GL. In thisembodiment, however, the dummy pixels are also formed in those portionsthat are arranged in parallel with the drain signal lines DL, thereby toform the dummy liquid crystal display portion DAR mentioned above.

<Constitution of Pixels>

FIG. 1 is a plan view illustrating the above-mentioned dummy pixel andanother pixel neighboring the dummy pixel according to an embodiment.Here, the dummy pixel is one of the dummy pixels arranged in parallelwith the drain signal line DL.

FIG. 4 is a sectional view along the line 4-4 of FIG. 1, and FIG. 5 is asectional view long the line 5-5 of FIG. 1. In these drawings, the gatesignal lines GL are formed on the surface of the transparent substrateSUB1 on the side of the liquid crystals, the gate signal lines GLextending in the x-direction and being arranged in parallel in they-direction. These gate signal lines GL surround rectangular regionstogether with the drain signal lines DL that will be described later,the regions constituting the pixel regions.

On the surface of the transparent substrate SUB1 on which the gatesignal lines GL are formed, there is formed an insulating film GI of SiNso as to also cover the gate signal lines GL. The insulating film GIexhibits the function as an interlayer insulating film for the gatesignal lines GL in the region where there are formed the drain signallines DL that will be described later, and the function as a gateinsulating film in the region where there are formed thin-filmtransistors TFT that will be described later.

A semiconductor layer AS of, for example, amorphous silicon is formed onthe surface of the insulating film GI so as to be overlapped on portionsof the gate signal lines GL. The semiconductor layer AS is that of thethin-film transistor TFT and has a drain electrode SD1 and a sourceelectrode SD2 formed on the upper surface thereof, thereby to constitutea MIS (metal insulator semiconductor) transistor of an inverse staggerstructure using part of the gate signal line as the gate electrode.Here, the drain electrode SD1 and the source electrode SD2 aresimultaneously formed at the time of forming the drain signal line DL.

That is, there are formed drain signal lines DL extending in they-direction and being arranged in the x-direction, the drain signallines DL partly extending up to the upper surface of the semiconductorlayer AS to thereby form drain electrodes SD1. There are further formedsource electrodes SD2 being separated away from the drain electrodes SD1by the channel length of the thin-film transistor TFT. Here, the drainsignal lines DL have a plurality of bending portions in a direction inwhich they extend and are formed in a zig-zag shape. In this embodiment,the bending portions are formed, for example, in the portions where thegate signal line GL is formed, in the central portions of the pixelregions and in the portions where the next gate signal line GL isformed.

The source electrodes SD2 are formed integrally with the pixelelectrodes PX that are formed in the pixel regions. Namely, the pixelelectrodes PX serve as the source electrodes SD2 at the ends on one sidethereof, and are constituted by electrodes which are extending in they-direction nearly at the centers of the pixel regions. Further, thepixel electrodes are bent at the centers thereof and are formed in sucha pattern that the drain signal lines DL are partly shifted in thex-direction.

A protection film is formed on the surface of the transparent substrateSUB1 on which are formed thin-film transistors TFT, drain signal linesDL, drain electrodes SD1, source electrodes SD2 and pixel electrodes PX.The protection film avoids the thin-film transistors TFT from cominginto direct contact with the liquid crystals, and prevents thecharacteristics of the thin-film transistors TFT from beingdeteriorated. The protection film is constituted by a laminate of aprotection film PAS formed of an inorganic material layer such as of SiNand a protection film OPAS formed of an organic material layer such asof a resin. In the drawing, the region where the protection film OPAS isformed is denoted by OPAS, which is the same also in other drawings. Asdescribed above, at least the organic material layer is used as theprotection film in order to lower the dielectric constant of theprotection film itself.

The counter electrodes CT are formed on the upper surface of theprotection film OPAS. The counter electrodes CT are constituted bygroups of a plurality of electrodes (two in the drawing) which areextending in the y-direction and are arranged in parallel in thex-direction. When viewed on a plane, these electrodes are positionedwith the pixel electrode PX therebetween.

Here, the counter electrodes CT are formed in overlapping relationshipon the drain signal lines DL with the center axes in agreementtherewith, and having a width greater than the width of the drain signallines DL. With the counter electrodes CT having a width greater thanthat of the drain signal lines DL, the lines of electric force from thedrain signal lines DL are effectively prevented from terminating at thecounter electrodes CT and terminating at the pixel electrodes PX. Whenthe lines of electric force from the drain signal lines DL terminate atthe pixel electrodes PX, there occurs noise. In this case, since theprotection film OPAS having a small dielectric constant is interposedbetween the counter electrodes CT and the drain signal lines DL, it isallowed to decrease the parasitic capacitance therebetween.

The counter electrodes CT constituted by groups of electrodes are formedintegrally with the counter voltage signal lines CL which are formed tofully cover the gate signal lines GL and are formed of the samematerial, and are supplied with a reference voltage through the countervoltage signal lines CL. The counter voltage signal lines CL which fullycover the gate signal lines GL have the ends on the other side of thepixel electrodes PX positioned thereunder in the portions that aredeviated beyond the gate signal lines GL and, whereby, capacitorelements Cstg are formed between the pixel electrodes PX and the countervoltage signal lines CL with protection films PAS and OPAS as dielectricfilms. The capacity elements Cstg work to store the video signals fedto, for example, the pixel electrodes PX for relatively extended periodsof time.

An orientation film (not shown) is formed on the upper surface of thetransparent substrate SUB1 on which the counter electrodes CT are formedcovering the counter electrodes CT. The orientation film is the one thatcomes in direct contact with the liquid crystals, and determines thedirection of the initial orientation of molecules of the liquid crystalsdepending upon the rubbing formed on the surface thereof.

Even if the protection film OPAS may happen to peel off starting fromthe end thereof in the thus constituted liquid crystal display device,the peeling ceases to proceed in the region of the dummy liquid crystaldisplay portion DAR and is prevented from advancing to the liquidcrystal display portion AR inside the dummy liquid crystal displayportion DAR.

Here, the drain signal lines DL, dummy counter electrodes CT and dummypixel electrodes PX have been formed in a zig-zag pattern in the dummyliquid crystal display portion DAR. Therefore, the peeling force of theprotection film OPAS is relaxed, and the protection film OPAS isprevented from being peeled off over a wide area at one time.

In this constitution, further, if there is maintained such arelationship that thickness of the protection film OPAS>thickness of theprotection film PAS>thickness of the electrodes under the protectionfilm PAS, then, the thickness of the electrodes under the protectionfilm appears on the surface of the protection film, and the contact areaincreases. This enhances the adhesion to the lower layer of the organicfilm OPAS decreasing the chances of peeling.

Embodiment 2

FIG. 6 is a sectional view illustrating another embodiment of the liquidcrystal display device of the invention and corresponds to FIG. 5. Thisembodiment differs from FIG. 5 in that use is made of the protectionfilm OPAS of the organic material layer only without using theprotection film PAS of the inorganic material layer. In this case, too,the same effect is obtained as a matter of course.

Embodiment 3

FIG. 7 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention and corresponds to FIG.5. This embodiment differs from FIG. 5 in that the pixel electrodes PXare formed on the upper surface of the protection film OPAS like thecounter electrodes CT. The contact between the pixel electrodes PX andthe source electrodes SD2 of the thin-film transistors TFT isaccomplished using through-holes formed in the protection film OPAS. Inthis case, too, the same effect is obtained as a matter of course.

Embodiment 4

FIG. 8A is a plan view illustrating a further embodiment of the liquidcrystal display device of the invention, and corresponds to FIG. 1. FIG.8B is a sectional view along the line 8 b-8 b of FIG. 8A. Thisembodiment differs from FIG. 5 in that the pixels in the dummy liquidcrystal display portion DAR are simply formed as a pattern PPP forpreventing the peeling of the protection film OPAS instead of beingformed as dummy pixels, the pattern closely resembling that of thepixels. Hereinafter, the region forming the peel-preventing pattern isdenoted as PPP.

Namely, in the liquid crystal display portions AR and PPP, there isformed the counter voltage signal line CL in common for the pixels thatare arranged in the x-direction in the same layer as the gate signalline GL, the counter voltage signal line CT being connected to thecounter electrodes CT in the ordinary pixels (pixels in the effectivedisplay region) via through-holes TH formed penetrating through theprotection films OPAS and PAS. This makes it possible to lower theover-all electric resistance of the counter electrodes CT formed of, forexample, a light-transmitting material.

In the portions which closely resemble the pixels in the liquid crystaldisplay portion formed as the peel-preventing pattern, the countervoltage signal line CL is integrally formed with the counter electrodesCT. Namely, in these portions, the counter electrodes CT are formed tosubstitute for the pixel electrodes PX.

In this case, too, there is exhibited the same effect as that of thecase of Embodiment 1. When thus constituted, it is allowed to greatlydecrease the voltage differential in the portions closely resembling thepixels in the liquid crystal display portion DAR formed as thepeel-preventing pattern and, hence, to suppress the occurrence of theso-called electrolytic corrosion. This also makes it possible to avoidthe peeling of the protection film OPAS caused by the electrolyticcorrosion when the device is really used.

Embodiment 5

FIG. 9 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.8B. This embodiment differs from that of FIG. 8B in that the othercounter electrodes CT are formed separately as well as the counterelectrodes CT that are formed on the protection film OPAS instead offorming the counter voltage signal line CL in the portions closelyresembling the pixels in the peel-preventing pattern region PPP. Thereare exhibited the same effects as those of the embodiment 4.

Embodiment 6

FIG. 10A is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.8. FIG. 10B is a sectional view along the line 10 b-10 b of FIG. 10A.This embodiment differs from that of FIG. 8 in that a plurality of thecounter electrodes CT are formed integrally with the counter voltagesignal line CL in the portions closely resembling the pixels in thepeel-preventing pattern. Namely, the protection film OPAS is formed onthe surface of the protection film PAS that is forming a step of thecounter electrodes CT, and the adhering strength is improved.

Embodiment 7

FIG. 11A is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 8A. FIG. 11B is a sectional view along the line 11 b-11 b ofFIG. 11A, and corresponds to FIG. 8B. This embodiment differs from thatof FIG. 8B in that a material layer is formed on the upper surface ofthe insulating film GI so as to be overlapped on the counter electrodesCT of the lower layer in the portions closely resembling the pixels inthe peel-preventing pattern region PPP. Here, the material layer issimultaneously formed at the time of forming the drain signal lines DL,and renders the steps (recesses and protuberances) formed thereby toappear conspicuously on the surface of the protection film PAS. Thismakes it possible to terminate the peeling from the end surface of theprotection film OPAS at this portion, and prevents the peeling fromsubstantially reaching the liquid crystal display portion AR.

Embodiment 8

FIG. 12 is a view illustrating a further embodiment of the liquidcrystal display device according to the invention, i.e., is a plan viewillustrating a right upper corner portion of the liquid crystal displayportion AR.

In the embodiments described above, the drain signal lines DL, pixelelectrodes PX and counter electrodes CT were formed in a zig-zag mannersubstantially in the pixel regions in the liquid crystal display portionAR. They, however, may be formed straight. In FIG. 12 in which thepixels are denoted by PIXEL, the signal lines in the pixels are formedstraight. The object can be accomplished if the drain signal lines DL,pixel electrodes PX and counter electrodes CT are formed in a zig-zagshape in only those portions corresponding to the dummy liquid crystaldisplay portion DAR.

Embodiment 9

FIG. 13A is a plan view illustrating part of the liquid crystal displaydevice according to a further embodiment of the invention, and FIG. 13Bis a sectional view along the line 13 b-13 b in FIG. 13A.

Substantially in the periphery of the liquid crystal display portion AR,there is no pattern which nearly resembles the pattern in the pixelregions substantially in the liquid crystal display portion AR. Instead,openings are formed in a scattered manner or arranged in parallel in theinsulating film GI of these portions. These openings may be in the shapeof holes or grooves. Thus, a number of recesses and protuberances areformed on the surface of the insulating film GI to reinforce theadhering force to the protection film OPAS formed on the surfacethereof, so that it will not be peeled off.

Embodiment 10

FIG. 14 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.13B. This embodiment differs from that of FIG. 13B in that theprotection film PAS is formed on the upper surface of the insulatingfilm GI, and openings are formed in a scattered manner or in parallel inthe protection film PAS as well as in the insulating film GI. In thiscase, too, there are exhibited the same effects as those of theembodiment 9.

Embodiment 11

FIG. 15 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.14. This embodiment differs from that of FIG. 14 in that the opening isformed in neither the insulating film GI nor the protection film PASbut, instead, a number of material layers are formed in a scatteredmanner or being arranged in parallel on the surface of the insulatingfilm GI in order to form recesses and protuberances in the peel-preventpattern region PPP. In the case of this embodiment, the material layersare formed simultaneously with the formation of, for example, the drainsignal lines DL.

FIGS. 16A to 16F illustrate examples of patterns of many material layersarranged in a scattered manner or in parallel according to theembodiment 11. FIG. 16A shows a pattern forming a plurality ofprotuberances and recesses, FIG. 16B shows a pattern in which theprotuberances and recesses are formed in a deviated manner, FIG. 16Cshows a pattern of slits or stripes, FIG. 16D shows a pattern of slitsor stripes that are bent, FIG. 16E shows a pattern in which a pluralityof slits are formed in an inclined manner, and FIG. 16F shows a patternin which the sizes of protuberances and recesses gradually differ.

Embodiment 12

FIG. 17A is a view of the constitution of a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.13A. FIG. 17B is a sectional view along the line 17 b-17 b in FIG. 17A.This embodiment differs from that of FIG. 13 A and FIG. 13B in thatopenings are formed in the protection film OPAS itself to prevent theprotection film OPAS from being peeled off. In this case, the openingsOPNG are formed in a plural number from the end of the protection filmOPAS toward the side of the liquid crystal display portion AR, theopenings near the end of the protection film OPAS being greater than theopenings on the side of the liquid crystal display portion AR. Thismakes it possible to prevent the protection film OPAS from being peeledoff at one time. Here, the openings have different sizes as describedabove so as to cope with the peeling force that may be produced in casethe protection film OPAS is being peeled off.

Embodiment 13

FIG. 18 is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 17B. This embodiment differs from that of FIG. 17 in that acheck terminal TTNL is formed in the region of opening formed in theprotection film OPAS covering the opening. Here, the check terminal isthe one for checking the breakage of the drain signal line DL or thegate signal line GL in the step of producing the liquid crystal displaydevice, and is often cut away from the drain signal line DL or the gatesignal line GL before the liquid crystal display device is finished.Covering the material of the check terminal prevents such an occurrencethat various solutions infiltrate through the openings formed in theprotection film OPAS to promote the peeling of the protection film OPAS.

Embodiment 14

FIG. 19A is a plan view illustrating a further embodiment of the liquidcrystal display device of the invention. FIG. 19B is a sectional viewalong the line 19 b-19 b of FIG. 19A.

In this embodiment, a drive circuit DRVC is formed in a portion of theregion substantially surrounding the liquid crystal display portion AR.The drive circuit is a scanning signal drive circuit V or a video signaldrive circuit He, and is fabricated by directly forming thin-filmtransistors and a wiring layer for connecting them on the transparentsubstrate SUB1. As the semiconductor material SCN of the thin-filmtransistors, there is used polysilicon, polycrystalline silicon,continuous grain boundary silicon or CGS. If these circuits are formedunder the protection film OPAS, complex ruggedness on the surfaces ofthe circuits contributes to improving the adhesion of the protectionfilm OPAS and preventing the peeling.

Embodiment 15

FIG. 20 is a plan view illustrating a further embodiment of the liquidcrystal display device of the invention. FIG. 20 illustrates a portionwhere the gate signal lines GL are connected to the scanning signaldrive circuit V. The bump gap for connecting the scanning signal drivecircuit V to the gate signal lines GL is smaller than the gap among thegate signal lines GL neighboring to one another. Therefore, there existsa portion where the gate signal lines GL converge to the scanning signaldrive circuit V.

In this embodiment, the edge of the protection film OPAS is so arrangedas to traverse the portion where the gate signal lines GL converge. Inthis case, some of the gate signal lines GL run aslant with respect tothe edge of the protection film OPAS. Because of this reason, theprotection film OPAS is unlikely to peel off starting from the edge.

This embodiment has been described in relation to the portion where thegate signal lines GL are connected to the scanning signal drive circuitV. The same constitution may be employed even for a portion where thedrain signal lines DL are connected to the video signal drive circuitHe. Besides, the two constitutions may be used in combination, as amatter of course.

Embodiment 16

FIG. 21A to FIG. 21E are plan views illustrating a further embodiment ofthe liquid crystal display device of the invention. FIG. 21A to FIG. 21Eshow the edge of the protection film OPAS. The edge has a rugged shapein FIG. 21A, the edge has a zig-zag shape in FIG. 21B, the edge has adeformed zig-zag shape in FIG. 21C, the edge having a random shape inFIG. 21D, and the edge has a curved shape in FIG. 21E.

In these cases, too, the protection film OPAS can be prevented frombeing peeled off starting from the edge. Therefore, the protection filmOPAS may be formed alone or may be formed in combination with theabove-mentioned embodiments.

The effect increases with a decrease in the period of the repetitivepattern that is shown in FIG. 21. Concretely speaking, it is desiredthat a period consists of from one pixel to several pixels.

Embodiment 17

FIG. 22 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention. FIG. 22 shows the edgeof the protection film OPAS.

In FIG. 22, the wiring WRN constituting the gate signal line GL or thedrain signal line DL is formed of aluminum (Al) or an alloy containingaluminum, and a protection film OPAS of an organic material layer isformed on the upper surface of the inorganic film (insulating film GI,or a laminate of the insulating film GI and the protection film PAS ofthe inorganic material layer). Openings are formed in the inorganic filmfor exposing portions of the gate signal lines GL or the drain signallines DL in the peripheries of the region which substantially works asthe liquid crystal display portion AR, the openings being covered withthe protection film OPAS. When thus constituted, so-called hillocksdevelop from the gate signal line GL or the drain signal line DL in theregion where the opening is formed in the inorganic film, the hillocksgrowing to a degree long enough to arrive at the protection film OPAS.Due to the hillocks, therefore, the protection film OPAS is preventedfrom peeling off.

Embodiment 18

FIG. 23 is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 22. This embodiment differs from that of FIG. 22 in that thewiring WRN formed of aluminum (Al) or an alloy containing aluminum andconstituting the gate signal line GL or the drain signal line DL, iscovered with a metal layer WRN2 which is formed on thealuminum-containing wiring WRN to protect the wiring WRN from thehillocks. Openings are formed in the metal layer WRN2 as well as in theinorganic film GI, in the peripheries of the region which substantiallyworks as the liquid crystal display portion AR.

The metal layer is formed of, for example, molybdenum or an alloycontaining molybdenum, and reliably prevents the occurrence of hillockson the region serving substantially as the liquid crystal displayportion AR. The metal layer works to decrease the connection resistanceto the external unit.

Embodiment 19

FIG. 24 is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 23. This embodiment differs from that of FIG. 23 in that thewiring WRN formed of aluminum (Al) or an alloy containing aluminum andconstituting the gate signal line GL or the drain signal line DL, isanodically oxidized over the surfaces thereof so as to form an aluminumoxide layer Al₂0₃ thereon.

A portion from which the aluminum oxide is removed is existing in theperipheries of the region which substantially serves as the liquidcrystal display portion AR. No opening is formed in the inorganic filmcovering the gate signal line GL or the drain signal line DL and fromwhich the aluminum oxide has been removed. The protection film OPAS isformed on the upper surface of the inorganic film. Hillocks are formedfrom the gate signal line GL or the drain signal line DL through theportion from which the aluminum oxide is removed and through theinorganic film up to the protection film OPAS, so that the protectionfilm OPAS is not peeled off.

Embodiment 20

FIG. 25 is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 24. This embodiment differs from that of FIG. 24 in that theopening is formed in the inorganic film, too, in agreement with theportion where there is no aluminum oxide layer Al₂0₃ on the wiring WRNwhich constitutes the gate signal line GL or the drain signal line DL.This allows the hillocks to easily and efficiently grow on theprotection film OPAS.

Embodiment 21

FIG. 26A is a plan view illustrating a further embodiment of the liquidcrystal device of the invention. FIG. 26B is a sectional view along theline 26 b-26 b of FIG. 26A.

FIG. 26A is a plan view showing the right upper corner portion of theliquid crystal display portion AR. A covering layer CVL is formed alongthe end surfaces of the protection film OPAS to cover the wholecircumference thereof. As the covering layer CVL, there may be used anyone of the organic film, inorganic film, transparent conducting layer ormetal material. Namely, the edges of the protection film OPAS that tendto be easily peeled off, are covered with the covering layer CVL.

Embodiment 22

FIG. 27 is a plan view illustrating a further embodiment of the liquidcrystal display device of the invention, and corresponds to FIG. 26(a).This embodiment differs from that of FIG. 26(a) in that the coveringlayers CVL are discretely formed along the edges of the protection filmOPAS. This exhibits the same effect as that of the case of embodiment21.

Embodiment 23

FIG. 28 is a plan view illustrating a further embodiment of the liquidcrystal display device of the invention, and corresponds to FIG. 26B.This embodiment differs from that of FIG. 26B in that an electricallyconducting layer is used as the covering layer CVL for covering theedges of the protection film OPAS. In this case, it is desired that theelectrically conducting layer is formed simultaneously with theformation of the electrodes PE such as counter electrode. This does notcause an increase in the number of the production steps, and protectsthe side wall surfaces at the edges of the protection film OPAS fromcoming in contact with the developing solution, washing solution,etching solution or resist-peeling solution used for patterning theelectrodes.

FIGS. 29A to 29E are diagrams of steps illustrating an embodiment offorming the electrically conducting layer simultaneously with theformation of the electrodes PE. In FIG. 29A, an electrode layer MTL thatbecomes the electrode is formed on the organic protection film OPAS andon the inorganic insulating film GI and in FIG. 29B, a resist RGST isformed thereon. In the step of patterning the resist shown in FIG. 29C,the end surfaces of the protection film OPAS are protected from theresist-developing solution by the resist RGST and by the electrodelayer. In the step of etching the electrode layer shown in FIG. 29D, theend surfaces of the protection film OPAS are protected from the etchingsolution by the resist and by the electrode layer. In the step ofpeeling the resist shown in FIG. 29E, the end surfaces of the protectionfilm OPAS are protected from the resist-peeling solution by theelectrode layer CVL.

Embodiment 24

FIG. 30 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.28. This embodiment differs from that of FIG. 28 in that theelectrically conducting material CVL covering the end surfaces of theprotection film OPAS is electrically connected to the signal line WRN(gate signal line GL or the drain signal line DL) formed under theinorganic film GI to thereby constitute a terminal. This terminal can beused as the terminal TT for conducting the checking. In FIG. 30, theterminal is connected to the signal line using the through-hole formedin the inorganic film. As shown in FIG. 31, however, they may beconnected together using the through-hole formed penetrating through theprotection film OPAS and the inorganic film, as a matter of course.

Embodiment 25

FIG. 32 is a sectional view illustrating a further embodiment of theliquid crystal display device of the invention, and corresponds to FIG.26B. This embodiment differs from that of FIG. 26B in that the angle θof the end surface of the protection film OPAS with respect to thesurface of the transparent substrate SUB1 is set over a range of from10° to 80°. When the angle is greater than 80°, the protection film OPASis not formed to a sufficient degree and the wiring tends to becomebroken. When the angle is smaller than 10°, on the other hand, thedistance becomes too great between the upper side and the lower side inthe sectional structure of the protection film OPAS, and the endsurfaces of the protection film OPAS tend to be ripped off. When thecovering layer CVL is formed to also work as a checking electrode, it isdesired that the angle θ of the end surface of the protection film OPASrelative to the surface of the transparent substrate SUB1 is in a rangeof from 10° to 70°. This is such that the probe can be brought intocontact therewith at the time of checking.

Referring further to FIG. 33, it is desired that the covering layer CVLprotrudes beyond the lower edge of the protection film OPAS by an amountL which is not smaller than 10 μm. This is to prevent the lower edge ofthe protection film OPAS from floating.

Embodiment 26

FIG. 34A is a plan view illustrating a further embodiment of the liquidcrystal device of the invention, and FIG. 34B is a sectional view alongthe line 34 b-34 b of FIG. 34A. FIG. 34A is a plan view showing theright upper corner portion of the liquid crystal display portion AR. Theconstitution of the pixels is nearly the same as the one shown in FIG. 1(in this case, the drain signal lines DL, pixel electrodes PX andcounter electrodes CT may be straight), and the counter electrodes CTare formed on the upper surface of the protection film OPAS.

The covering layer CVL covering the end surfaces of the protection filmOPAS permits the counter electrode CT to extend. In this case, the areaof the covering layer CVL covering the protection film OPAS greatlyincreases to nearly completely prevent the peeling of the protectionfilm OPAS. The covering layer CVL also works as the counter voltagesignal line CL for supplying the voltage to the counter electrodes CT,and makes it possible to greatly decrease the electric resistance.

When a dummy liquid crystal display portion DAR or the like is formedclose to the region which substantially works as the liquid crystaldisplay portion AR, the electrodes formed on the protection film OPAS ofthe pixel regions in the dummy liquid crystal display portion DAR may beextended so as to form the covering layer CVL, as a matter of course.

Embodiment 27

FIGS. 35 to 38 are views illustrating patterns of the covering layer CVLcovering the edges of the protection film OPAS.

FIG. 35 shows the covering layers being discretely formed along theedges of the protection film OPAS, FIG. 36 shows the covering layerformed along the edge which is in parallel with the y-direction amongthe edges of the protection film OPAS, FIG. 37 shows the covering layersbeing independently formed along the edge in parallel with thex-direction and along the edge in parallel with the y-direction of theprotection film OPAS, and FIG. 38 shows the covering layer continuouslyformed along the edge in parallel with the x-direction and along theedge in parallel with the y-direction of the protection film OPAS. Here,it needs not be pointed out that the patterns of the covering layers CVLcovering the edges of the protection film OPAS are not limited to onlythose described above.

Embodiment 28

FIG. 39A and FIG. 39B are views illustrating the constitution of afurther embodiment of the liquid crystal display device of theinvention, and corresponds to FIG. 34A and FIG. 34B. This embodimentdiffers from that of FIG. 34 in that the edges of the protection filmOPAS are covered by the extended portion of the counter electrode CT(playing the role of the covering layer CVL) formed on the upper surfaceof the protection film OPAS and by the terminal TT for checking. Thatis, in the region where the terminal TT for checking is formed, theextending portion of the counter electrode CT avoids the above regionand covers the edge of the protection film OPAS in the regions otherthan the above avoided region.

This constitution is in no way limited to the one in which theelectrodes are formed on the upper surface of the protection film OPAS,but may be such that as shown in FIG. 40, the edges of the protectionfilm OPAS are covered with the terminals TT for checking, such asseparate materials CVL which are alternately arranged.

Embodiment 29

FIG. 41A is a view illustrating the constitution of a further embodimentof the liquid crystal display device of the invention, and correspondsto FIG. 39A. FIG. 41B is a sectional view including a pair of substratesof this embodiment. This embodiment differs from that of FIG. 39 in thata portion is clarified for forming a sealing member SL. The sealingmember SL is formed being overlapped on the covering layer CVL which isextending from the edge of the protection film OPAS to the edge of thetransparent substrate SUB1.

The covering layer CVL is prevented by the sealing member SL from beingpeeled off, which, then, makes it possible to reliably prevent theprotection film OPAS from being peeled off. In particular, theresistance against vibration and shock is improved after the device iscompleted as a product. From the same point of view, the same effect isexhibited even when the sealing member SL is formed along the edges ofthe protection film OPAS as shown in, for example, FIG. 42.

Embodiment 30

The above-mentioned embodiments have dealt with the liquid crystaldisplay devices. In the organic EL display device, too, however, thegate signal lines and drain signal lines are formed on the surface ofthe substrate in the same pattern as the one described above. Besides,the organic material layer is formed on nearly the whole displaysurface. It, therefore, needs not be pointed out that the invention canfurther be adapted to any other display devices that include the organicEL display device.

The constitution of the organic EL display device will now beschematically described.

FIG. 43A is a plan view illustrating an embodiment of the organic ELdisplay device, FIG. 43B is a sectional view along the line 43 b-43 b ofFIG. 43A, FIG. 43C is a sectional view along the line 43 c-43 c of FIG.43A, and FIG. 43 d is a sectional view along the line 43 d-43 d of FIG.43A.

In these drawings, a semiconductor layer PS of a polysilicon layerextending in the x-direction is formed in, for example, a left lowerportion of each pixel region on the surface of the substrate SUB. Thesemiconductor layer PS also serves as a semiconductor layer of thethin-film transistors TFT.

An insulating film GI is formed on the surface of the substrate SUBcovering the semiconductor layer PS. The insulating film GI serves as agate-insulating film in the region where the thin-film transistors TFTare formed. On the surface of the insulating film GI, there are formedgate signal lines GL which are extending in the x-direction and arearranged in parallel in the y-direction. The gate signal lines GL definethe pixel regions together with the drain signal lines DL that will bedescribed later. The gate signal line GL has a portion that is extendingtraversing nearly the central portion of the semiconductor layer PS, andthe extending portion works as a gate electrode GT of the thin-filmtransistor TFT.

After the gate electrode GT has been formed, impurity ions are injectedwith the gate electrode GT as a mask, and the semiconductor layer PSassumes a decreased resistance in the regions except the region justunder the gate electrode GT. An insulating film IN is formed on thesurface of the substrate SUB covering the gate signal line GL (gateelectrode GT). The insulating film IN works as an interlayer insulatingfilm for the gate signal lines GL in the region where there are formedthe drain signal lines DL that will be described later. On the surfaceof the insulating film IN, there are formed drain signal lines DL thatare extending in the y-direction and are arranged in parallel in thex-direction. The drain signal lines DL have portions that are extendingup to an end of the semiconductor layer PS, and are connected to thesemiconductor layer PS via through-holes that have been formed inadvance penetrating through the insulating film IN and the insulatingfilm GI. Namely, the extending portions of the drain signal lines DLwork as drain electrodes SD1 of the thin-film transistors TFT. Thesource electrode SD2 is connected to the other end of the semiconductorlayer PS via the through-hole that has been formed in advancepenetrating through the insulating film IN and the insulating film GI,the source electrode SD2 having an extending portion for connection tothe pixel electrode PX that will be described later.

An insulating film IL is formed on the surface of the substrate SUB onwhich are formed the drain signal lines DL (drain electrodes SD1) andthe source electrodes SD2. On the upper surface of the insulating filmIL, there is formed a pixel electrode PX on the center of each pixelregion except small peripheral portions. The pixel electrode PX isconnected to the source electrode SD2 of the thin-film transistor TFTvia the through-hole formed in the insulating film IL.

A light-emitting material layer FLR is formed on the upper surface ofthe pixel electrode PX via a hole injection layer HP. The light-emittingmaterial layer FLR is divided from the light-emitting material layer ofother neighboring pixel regions via a bank film BNK which comprises anorganic material layer. The bank film is one of organic film whichconstitutes each of pixel regions.

A counter electrode CT is formed on the upper surfaces of thelight-emitting material layer FLR and of the bank film BNK in common forthe pixel regions, and a protection film PSV is formed on the uppersurface of the counter electrode CT. An electric current flows into thelight-emitting material layer FLR interposed between the pixel electrodePX and the counter electrode CT, whereby the light-emitting materiallayer FLR emits light. By forming at least either one of the pixelelectrode PX or the counter electrode CT by using a light-transmittingelectrically conducting material such as ITO, IZO or ITZO, the light canbe seen by eyes.

The thus constituted organic EL display device uses an organic materiallayer in the display portion and has an electrically conducting filmformed on the upper surface thereof. Therefore, the organic EL displaydevice is placed under the same circumstances as the liquid crystaldisplay device described above, and has the same problem.

Therefore, the above-mentioned embodiments can be adapted to the organicEL display device, because organic EL display device includes organicfilms such as protection film PSV and bank film BNK.

According to the display device of this invention as will be obviousfrom the foregoing description, it is possible to prevent the organicmaterial layer from being peeled off.

1. A display device comprising: a substrate having a display portion anda peripheral portion; a plurality of gate signal lines and a pluralityof drain signal lines formed over the substrate; a plurality ofswitching elements connected to the plurality of gate signal lines andthe plurality of drain signal lines and formed over the substrate; aplurality of pixel electrodes connected to the plurality of switchingelements and formed in the display portion; and an organic interlayerfilm formed in the display portion and the peripheral portion; wherein acovering layer is formed on the organic interlayer film in theperipheral portion.
 2. A display device according to claim 1, whereinthe covering layer is formed on a portion of an end surface of theorganic interlayer film in the peripheral portion.
 3. A display deviceaccording to claim 2, wherein the covering layer is made of atransparent conductive material.
 4. A display device according to claim3, wherein the covering layer is made of a material which is the same asa material of the plurality of pixel electrodes.
 5. A display deviceaccording to claim 2, wherein the covering layer is made of a metallayer.
 6. A display device according to claim 5, wherein the coveringlayer is a testing terminal of the display device.
 7. A display deviceaccording to claim 2, wherein the display device is an organic ELdisplay device, and the organic interlayer film is a bank film of theorganic EL display device.
 8. A display device according to claim 1,wherein the covering layer is made of a material which is the same as amaterial of the plurality of pixel electrodes.
 9. A display deviceaccording to claim 1, further comprising a plurality of counterelectrodes formed adjacent to the plurality of pixel electrode, andwherein the covering layer is made of a material which is the same as amaterial of the plurality of counter electrode.
 10. A display devicecomprising: a substrate having a display portion and a peripheralportion; a plurality of gate signal lines and a plurality of drainsignal lines formed over the substrate; a plurality of switchingelements connected to the plurality of gate signal lines and theplurality of drain signal lines and formed over the substrate; aplurality of pixel electrodes connected to the plurality of switchingelements and formed in the display portion; and an organic interlayerfilm formed in the display portion and the peripheral portion; wherein afirst insulating film is formed between the plurality of gate signallines and the plurality of drain signal lines; and wherein apeel-preventing pattern is disposed above the substrate in relation tothe first insulating film in the peripheral portion, and thepeel-preventing pattern is made by a layer that is the same layer as theplurality of gate signal lines.
 11. A display device according to claim10, wherein the peel-preventing pattern is disposed between thesubstrate and the first insulating film.
 12. A display device accordingto claim 11, wherein the display device is a liquid crystal displaydevice, and the first insulating film is a gate insulating film.
 13. Adisplay device according to claim 12, further comprising a secondinsulating film formed between the gate insulating film and the organicinterlayer film.
 14. A display device comprising: a substrate having adisplay portion and a peripheral portion; a plurality of gate signallines and a plurality of drain signal lines formed over the substrate; aplurality of switching elements connected to the plurality of gatesignal lines and the plurality of drain signal lines and formed over thesubstrate; a plurality of pixel electrodes connected to the plurality ofswitching elements and formed in the display portion; and an organicinterlayer film formed in the display portion and the peripheralportion; wherein a first insulating film is formed between the pluralityof drain signal lines and the organic interlayer film; and wherein apeel-preventing pattern is disposed above the substrate in relation tothe first insulating film in the peripheral portion, and thepeel-preventing pattern is made by a layer that is the same layer as theplurality of drain signal lines.
 15. A display device according to claim14, wherein the peel-preventing pattern is disposed between thesubstrate and the first insulating film.
 16. A display device accordingto claim 15, further comprising a gate insulating film formed betweenthe first insulating film and the substrate.
 17. A display deviceaccording to claim 15, wherein the display device is a liquid crystaldisplay device.